on intel / amd cpus/boards:

use lm sensors:

apt-get install lm-sensors; # install
sensors-detect; # detect available temperature sensors, answer with YES usually

# monitor cpu temp every second
while true; do sensors|grep Core; sleep 1; clear; done;

service kmod start; # might help too

on arm cpus/boards:

script /scripts/cpu_temp.sh will monitor CPU temp and update every second.

this will show only the temp of ONE CORE?

#!/bin/bash

while true ; do

cpu_temp=$(< /sys/class/thermal/thermal_zone0/temp)
cpu_temp=$(($cpu_temp/1000))
echo $cpu_temp C

sleep 1;
clear;

done # executes COMMAND every second
wget 
chmod +x /scripts/cpu_temp.sh; # mark runnable
admin